The invention relates to a data communication network and, more particularly, to a method of automatically creating correspondence relationships between apparatus names and addresses, and a filtering rule, which are interlocked with address autoconfiguration of network apparatuses.
In a data communication network represented by the Internet, it is necessary to allocate an address to each network apparatus which communicates via the network. The address which is allocated to such a network apparatus needs to be a correct address which is not duplicated in the same network and conforms with a protocol specification.
As address configuration methods, there are a method wherein a general user manually sets the addresses of the network apparatuses and a method wherein the addresses are automatically set among the network apparatuses.
The following methods have been proposed with respect to the address autoconfiguration. In a case where there is one apparatus and it is connected to a server in a one-to-one correspondence relationship, address allocation by the PPP (Point-to-Point Protocol) is generally used. As a method of automating the address configuration to a plurality of apparatuses, the DHCP (Dynamic Host Configuration Protocol) has been standardized in the IP (Internet Protocol), and the NDP (Neighbor Discovery Protocol) has been standardized in the IPv6. Those protocols enable correct addresses to be automatically allocated to the apparatuses without the user's concern.
If the address configuration according to the above-mentioned art is used, first, in the method wherein the general user manually sets the addresses, there is a case where a communication trouble is caused by erroneous setting due to complicatedness of techniques regarding connection of the network apparatuses or necessity of special knowledge.
Next, in the method wherein the addresses are automatically set among the network apparatuses, until the network apparatuses are actually connected to the network or until power sources are turned on, the addresses which are allocated to the network apparatuses cannot be specified. Therefore, a database which needs the addresses of the network apparatuses as information cannot be previously set. As examples of such a kind of database, a filtering table in which whether a packet is forwarded or discarded in a router is determined and a table holding correspondence relationships between apparatus names and the addresses for name resolution by the DNS (Domain Name System) can be mentioned.
Since those databases cannot be previously set, when the network apparatuses are actually connected to the network and the addresses of the network apparatuses are specified, a setting operation of those databases has to be executed to the router or a DNS server. However, since the special knowledge of the network is necessary for the setting of those databases, it is difficult for the general user to do it.